Anode rod tightening apparatus for alumina electrolysis cells

ABSTRACT

An anode rod tightening apparatus for alumina electrolysis cells having main bus bars comprising the combination of a clamping device and a driving mechanism in which the clamping device is formed of a horizontally disposed shaft with a pair of levers articulated on the shaft and a nut member on each of the levers adapted to engage opposite screw-threaded sections on a screw member for displacement of the levers in the direction toward and away from each other responsive to turning movement of the screw and a jaw member on each lever adapted to engage the anode rod when the levers are apart and in which the driving mechanism comprises a double clamp for engaging laterally spaced apart portions of the shaft and a wrench mounted for vertical movement into and out of engagement with the screw to effect turning movement of the screw when in operative engagement therewith and a guide means along the rod for guiding the driving mechanism.

finite States Patent lnventor Daniel Duclaux 135 bis rue du fourbourg deRoubaix, Lille Nord, France Appl. No. 27,777 Filed Apr. 13, 1970Patented Dec. 14, 1971 Priority Apr. 14, 1969 France 6910161 ANODE RODTIGHTENING APPARATUS FOR ALUMINA ELECTROLYSIS CELLS 8 Claims, 11 DrawingFigs.

3,410,786 11/1968 Duclaux et al 204/245 X 3,434,955 3/1969 Duclaux204/243 X 3,484,856 12/1969 Bogantes 204/297 R Primary Examiner-John H.Mack Assistant Examiner-D. R. Valentine Attorney-McDougall, Hersh &Scott ABSTRACT: An anode rod tightening apparatus for aluminaelectrolysis cells having main bus bars comprising the combination of aclamping device and a driving mechanism in which the clamping device isformed of a horizontally disposed shaft with a pair oflevers articulatedon the shaft and a nut member on each of the levers adapted to engageopposite screw-threaded sections on a screw member for displacement ofthe levers in the direction toward and away from each other responsiveto turning movement of the screw and a jaw member on each lever adaptedto engage the anode rod when the levers are apart and in which thedriving mechanism comprises a double clamp for engaging laterally spacedapart portions of the shaft and a wrench mounted for vertical movementinto and out of engagement with the screw to effect turning movement ofthe screw when in operative engagement therewith and a guide means alongthe rod for guiding the driving mechanism.

PATENIED DEC] 4 l9?! SHEET 1 OF 8 FIG. 2

I N VENTOR. DA/V EL Ducmux PATENTEU DEC 1 4 l97| SHEET 3 OF 8 PATENIEU0m 4 Ian SHEET [1F 8 FIGS 4 gill/lig M a VIII/III] lllllvr SHEET S [If 8PATENTEU DEC 1 4 I971 P r /////A a PATENTED BEE I 4 I97! SHEET 5 [IF 8ANODE ROD TIGHTENING APPARATUS FOR ALUMINA ELECTROLYSHS CELLS Thisinvention relates to an anode rod tightening system for use on main barsof alumina electrolysis cells of prebaked anode types.

In electrolysis cells which make use of prebaked anodes, the anodes aresealed at the lower portion of rods which are fixed by clamping onto themain horizontal bars to provide a rigid assembly which represents theanodic system.

The anodic system is actuated by vertical movement in a downward stroketo compensate for the spending of the anodes thereby to maintain theinterpolar distance relatively constant.

The spending of the anodes requires replacement on the one hand andraising of the main bus bars when they arrive at the bottom end of theirstroke by the above-mentioned movement, on the other hand. The raisingof the bars should be performed without any movement of the anodes.

The changing of the anodes and the raising of the bus bars call forloosening of the connection rod-bus bars.

The tightening system of the rods on the main bus bars has a doublepurpose: to insure a satisfactory mechanical connection, and to performan electrical contact for maintaining a very low-voltage drop under theaction of the very highintensity current passing through each anode. Inmodern cells, this intensity can reach oreven exceed 10,000 amperes.

Tightening the connection to a pressure of 12,000 to 15,000 daN isdesired for such high-intensity currents. The tightening should, ofcourse, be measured and controlled so as to maintain the desireduniformity.

Presently, there exist several types of clamping devices. Most of theseare hand operated and procure insufficient tightening pressure as wellas insufficient control of tightening pressure.

Certain hand operated systems include a removable part which has to beremoved by hand to allow the extraction or setting of the anode rod.

Other systems do not have removable parts but include devices which canbe swung aside to permit the removal of the anode rod. These systems arecomplex and quite expensive or badly arranged for mechanical operationboth from the standpoint of changing of the anode and for raising thebus bars.

It is an object of this invention to provide a tightening system for theanode rods of the main bus bars of alumina electrolysis cells.

These and other objects and advantages of this invention willhereinafter appear and, for purposes of illustration, but not oflimitation, an embodiment of the invention is shown in the accompanyingdrawings, in which:

FIG. 1 is a side elevational view of the clamp embodying features ofthis invention, with the clamp shown in the tightened position;

FIG. 2 is a side elevational view similar to that of FIG. 1, showing theclamp in loosened position;

FIG. 3 is a front elevational view of the clamp shown in FIG.

FIG. 4 is a plan view of the clamp shown in FIG. 1;

FIG. 5 is a side elevational view of the lower portion of the clampingdevice embodying the features of this invention;

FIG. 6 is a side elevational view, partially in section, of the upperportion of the clamp shown in FIG. 5;

FIG. 7 is a front view, partially in cross section, of the clampingdevice shown in FIGS. 5 and 6;

FIG. 8 is an elevational view, partially in section, of the lowerportion of the driving mechanism installed on the clamping device;

FIG. 9 is an elevational view showing the assembly of the clamping andoperating devices in mounted position;

FIG. 10 is an elevational view similar to that of FIG. 9 showing thedevices in tightened position; and

FIG. 11 is an elevational view of the assembly in position after removalof a spent electrode.

The invention includes, on the one hand, a clamping device, and on theother hand, an operating mechanism. The clamping device is designed andbuilt to apply very high-tightening pressure and to be controlled andoperated by a special mechanism with tightening control. The operatingmechanism is designed to operate efficiently and safely on the clampingdevice. The clamping device and the operating mechanism are designed tocooperate one with the other to provide a homogeneous assembly adaptedto the various exacting requirements of operation.

The clamping device is also designed to facilitate its mechanicaloperation during raising of the bus bars. Finally, the clamping deviceis also arranged to operate in fitting relation with most efficient andeconomical shapes of anode rods.

The clamping device includes as essential elements two leversarticulated on a common shaft, two-nut trunnions mounted respectively oneach of the levers and a screw embodying separate portions havingopposite threads (a righthand thread and a left-hand thread), inoperative engagement with the nuts to adjust the levers in a directiontoward and away from each other. Each lever includes at least one jawwhich applies pressure onto the anode rods when the levers are moved inthe direction away from each other. The common shaft is supported on twohooks attached to the main bar and located on each side of the anoderod.

The operating mechanism includes as essential elements one double clampcapable of grasping the common shaft of the levers of the clampingdevice at each of its ends and which, for this purpose, extends furtherthan the supporting hooks, a means of guiding along the anode rod,embodying for example a roller provided with flanges mounted on a shaftattached to a frame supporting the double clamp and the wrench and inwhich the frame is located at the end of a vertical ram which permits anup and down stroke.

For a particular arrangement of the system, the ram can be located alongthe centerline of the tightening wrench thereby to permit transmissionof the last of its rotational movement. In this instance, the ram ismovable both in its vertical stroke and in rotation and it can betelescopically arranged.

Referring now to the drawings for a detailed description, the device hasfor its purpose the tightening of an anode rod 10 on a main bus bar 3.As shown in FIGS. 14, a pair of hooks l are attached in laterally spacedapart relation on the main bus bar 3 as by means of bolts 2. Levers 4and 5 are articulated on a horizontally disposed shaft 6 which issupported at its ends on the two hooks 1. In the tightened position, asshown in FIG. 1, the levers 4 and 5 apply pressure by the action of jaw7 on the anode 10. A screw 8, which includes two threaded portions, onea right-handed thread and another a left-handed thread, acts on nutsprovided with trunnions 9 to actuate the levers 4 and 5. The screw 8 isprovided with a head 81 adapted to receive a tool for effecting turningmovement.

In loosened position, shown in FIG. 2, the nuts 9, under the action ofthe opposite threads of the screw 8, are brought together when the screwis rotated in the required direction. The screw 8 does not movevertically since its head 81 is maintained in the socket of a wrenchthat is provided on the driving mechanism. It appears that the pin 6 isdisplaced to the left relative to the position shown in FIG. 1, which isnecessary to disengage it from the hooks by a vertical stroke.

As shown in FIGS. 5 and 8, the driving mechanism includes a double clamp12 which is constantly urged towards closed position by a coil spring 13and which is capable of grasping the pin 6 by each of its ends which,for this purpose, extend beyond the supporting hooks l; a tighteningsocket wrench I4 capable of acting on the head 81 provided on the doublescrew 8; a tightening device along the anode rod 10 formed, for example,by a roller 11 provided with side flanges and mounted for rotationalmovement on a shaft carried by a frame 111 which supports the doubleclamp 12 and the wrench 14. The frame 111 is located at the end of avertical ram 17 to permit its up and down stroke. The ram canadvantageously be located along the centerline of the tightening wrench14 so as to transmit, to the very end, its rotational movement. In thiscase, the ram is mounted for movement both in its vertical stroke andfor rotation and it can be telescopically arranged.

As shown in FIG. 5, the driving mechanism, after having run along theanode rod on roller 11, comes into position by clamping the movable jawsof the double clamp 12 onto pin 6. The jaws are tightened onto the pinby the coil spring 13.

The action of the spring can be, for example, completed by a smallcylinder, not shown. The rotation of the wrench operates to loosen theclamping device and bring the pin 6 in the direction towards the left inFIG. 5 or in the direction towards the anode.

As shown in FIG. 6, the tightening wrench 14 includes a socket head 14!mounted to cooperate with the head 81 of the screw 8. The tighteningclamp is mounted on bearings 142 to enable turning movement in the frame111.

As shown in FIG. 7, the roller 1] is mounted on ball bearings and thejaws of the clamp 12 are articulated directly on the pin 110. A liftingbell 15 has been shown to cover the top of the anode rod 10 and to graspit with hooks 16, for example.

FIG. 8 shows the device during its vertical stroke with the roller 1 llturning on the anode rod 10 for guiding movement.

As shown in FIGS. 9ll, the vertical ram 17, with its operating parts, isarticulated on a horizontal pin parallel to the main bus bar 3 andsupported by the lifting bell 15. A spring 13 engages the ram in amanner to hold the roller 11 in contact with the anode rod 10 and alsoagainst a slope provided for this purpose on the lifting bell 15 as theroller passes over the intermediate portion 21 integral with the liftingbell. The rotation of the wrench is actuated by a motor 18 which may bein the form of an electric, pneumatic or hydraulic motor.

This arrangement enables the device to advance while tightening itselfsuccessively on the rod 10 and the lifting bell l5 which, on the onehand, allows the device to be maintained along the lifting bell l5 andthus leaves the anode rod 10 completely free, and, on the other hand, itallows reset of the device with certainty on hooks 1 when operating inreverse, even in the case of lack of visibility.

The guiding ram 17 can be actuated in vertical movement by anelectromechanical jack or a pneumatic or hydraulic cylinder 24.

FIG. 10 shows the assembly when the bus bar 3 is in its lowest positionrelative to the anode rod 10, with the clamping device in loosenedposition. FIG. 11 shows it in a position after removal of a spent anodeand before grasping a new anode. The driving mechanism keeps theclamping device set back in place after the setting of a new anode inthe cell.

In FIGS. 8-1 1, the system is shown as being attached onto a machinehaving for one of its functions the change of spent anodes. The systemis suspended from the end of a rigid horizontally disposed arm 22 withthe lifting bell 15 being fixed, for example, to the end of the guidingram 23 adapted to be actuated in a vertical direction by a cylinder. Thepin 21 is attached to the upper portion of the two vertical armsintegral with the lifting bell 15.

It will be seen that the screw 8, which actuates the clamping device, isvertically disposed such that a vertical traveling movement issufficient to place the socket onto the head of the screw to permitrotational movement thereof.

It will be seen that the system described is applicable to the clampingof anode rods of electrolysis cells onto the main bus bars which supportthe anodes.

It will be understood that changes may be made in the details ofconstruction, arrangement and operation, without departing from thespirit of the invention, especially as defined in the following claims.

I claim:

1. An anode rod tightening apparatus for alumina electrolysis cellshaving main bus bars comprising the combination of a clamping device anda driving mechanism for the clamping device, said clamping devicecomprising a horizontally disposed shaft, a pair of levers articulatedon said shaft, an elongate screw member having one portion with aright-hand thread and another portion with a left-hand thread, a nutmember mounted respectively on each of the levers with one nut memberthreadab y engaglng one of the threaded portions and the other nutmember engaging the other of the threaded portions of said screw fordisplacement of the levers in the direction toward and away from eachother responsive to turning movement of said screw, a jaw member on eachlever in pressure engagement with an anode rod when the levers areapart, hooks mounted in laterally spaced apart relation on the bus barsfor supporting the shaft, said driving mechanism comprising a doubleclamp for engaging laterally spaced apart portions of the shaft, awrench vertically disposed relative the screw and mounted for verticalmovement into and out of engagement with the screw and for turningmovement for rotating the screw when in operative engagement therewith,and a guide means along the rod for guiding the driving mechanism.

2. An apparatus as claimed in claim 1 in which the hooks are located oneach side of an anode rod when in position of use.

3. An apparatus as claimed in claim 1 which includes a frame and inwhich the guiding system of the driving mechanism comprises a rollerhaving side flanges and mounted for rotational movement on the frame andin which the frame supports the double clamp and wrench.

4. An apparatus as claimed in claim I which includes a guiding ramaligned with the axis of the tightening wrench and mounted fortransmission of rotational movement to the wrench.

5. An apparatus as claimed in claim 4 in which the guiding ram includesa horizontal pin parallel to the main bus bar and on which the ram isarticulated for rocking movement, and a spring resiliently urging theguiding system into engagement with the anode rod.

6. An apparatus as claimed in claim 4 in which the guiding ram istelescopic.

7'. An apparatus as claimed in claim 5 in which the anode rod has anextension in the form of a slope and which includes a lifting bellhaving an intermediate portion connected to the slope.

8. An apparatus as claimed in claim 7 which includes a horizontal pincarried by the lifting bell and on which the guiding ram is pivotallymounted.

f i t 8 3

2. An apparatus as claimed in claim 1 in which the hooks are located oneach side of an anode rod when in position of use.
 3. An apparatus asclaimed in claim 1 which includes a frame and in which the guidingsystem of the driving mechanism comprises a roller having side flangesand mounted for rotational movement on the frame and in which the framesupports the double clamp and wrench.
 4. An apparatus as claimed inclaim 1 which includes a guiding ram aligned with the axis of thetightening wrench and mounted for transmission of rotational movement tothe wrench.
 5. An apparatus as claimed in claim 4 in which the guidingram includes a horizontal pin parallel to the main bus bar and on whichthe ram is articulated for rocking movement, and a spring resilientlyurging the guiding system into engagement with the anode rod.
 6. Anapparatus as claimed in claim 4 in which the guiding ram is telescopic.7. An apparatus as claimed in claim 5 in which the anode rod has anextension in the form of a slope and which includes a lifting bellhaving an intermediate portion connected to the slope.
 8. An apparatusas claimed in claim 7 which includes a horizontal pin carriEd by thelifting bell and on which the guiding ram is pivotally mounted.